47 lines
1.3 KiB
Markdown
47 lines
1.3 KiB
Markdown
---
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title: Compact object
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tags: object,array,recursion
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cover: shapes
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firstSeen: 2020-11-27T13:57:41+02:00
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lastUpdated: 2020-11-27T13:57:41+02:00
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---
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Deeply removes all falsy values from an object or array.
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- Use recursion.
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- Initialize the iterable data, using `Array.isArray()`, `Array.prototype.filter()` and `Boolean` for arrays in order to avoid sparse arrays.
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- Use `Object.keys()` and `Array.prototype.reduce()` to iterate over each key with an appropriate initial value.
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- Use `Boolean` to determine the truthiness of each key's value and add it to the accumulator if it's truthy.
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- Use `typeof` to determine if a given value is an `object` and call the function again to deeply compact it.
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```js
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const compactObject = val => {
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const data = Array.isArray(val) ? val.filter(Boolean) : val;
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return Object.keys(data).reduce(
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(acc, key) => {
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const value = data[key];
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if (Boolean(value))
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acc[key] = typeof value === 'object' ? compactObject(value) : value;
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return acc;
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},
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Array.isArray(val) ? [] : {}
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);
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};
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```
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```js
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const obj = {
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a: null,
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b: false,
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c: true,
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d: 0,
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e: 1,
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f: '',
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g: 'a',
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h: [null, false, '', true, 1, 'a'],
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i: { j: 0, k: false, l: 'a' }
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};
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compactObject(obj);
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// { c: true, e: 1, g: 'a', h: [ true, 1, 'a' ], i: { l: 'a' } }
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```
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